FACTORS CONTROLLING THE COMPETITION AMONG ROTATIONAL AND VIBRATIONAL-ENERGY TRANSFER CHANNELS IN GLYOXAL

The state-to-state transfer of rotational and vibrational energy has b een studied for S-1 glyoxal (CHOCHO) in collisions with D-2, N-2, CO a nd C2H4 using crossed molecular beams, A laser is used to pump glyoxal seeded in He to its S-1 zero point level with zero angular momentum a bout its top axis (K' = 0), The inelastic scattering to each of at lea st 26 S-1 glyoxal rotational and rovibrational levels is monitored by dispersed S-1-S-0 fluorescence. Various collision partners are chosen to investigate the relative influences of reduced mass and the collisi on pair interaction potential on the competition among the energy tran sfer channels, When the data are combined with that obtained previousl y from other collision partners whose masses range from 2 to 84 amu, i t is seen that the channel competition is controlled primarily by the kinematics of the collisional interaction, Variations in the intermole cular potential play strictly a secondary role.